The present invention relates to electric motor drive systems and more particularly to a method of automatically tuning up the speed loop in a motor drive system coupled to a load.
General purpose drives can be connected to electric motors with widely varying parameters. The motors in turn can be driving loads of different inertia. In order to achieve optimum motor performance in terms of damping and response time it is necessary to match drive parameters to the actual motor characteristics.
If the total system inertia reflected to the motor shaft is known the control parameters can be adjusted to achieve the desired damping and speed of response desired. Accurate system inertia information is usually not available. When a drive is installed in a factory it is necessary to adjust control system parameters while operating the motor coupled to the load. The adjustment is time consuming and involves repetitive trial and error adjustments. The adjustments typically can take two hours with difficult cases taking much longer. The results are satisfactory but certainly not optimal as far as damping characteristics and speed of response.
If optimum performance could be achieved, cycle time in performing repetitive operations calling for fast response times could be significantly reduced. It is an object of the present invention to automatically adjust the control parameters of the speed loop of a drive system to achieve a commanded operator response time while the drive system is connected to the load.
It is a further object of the present invention to automatically adjust the control parameters of the speed loop of a drive system in less than a minute, responsive to a desired system time selected by an operator.